Mary had a little lambda

Mary had a little lambda,
a function pure as snow.
And for every program that Mary wrote,
the lambda was all she needed to know.

Python’s lambda, a tiny anonymous function, can be useful in a pinch when you’re feeling too lazy to type that extra d-e-f. But did you know that behind this little lambda is actually one of the most powerful & elegant abstractions in the history of computer science?

The lambda calculus, dating back to the work of lambda shepherd Alonzo Church in the 1930’s, lets us represent our programs - all their logic and data - as pure, anonymous functions, using nothing but (a whole lot of) lambda. Let’s take it for a spin and see what we can create: booleans and conditionals, integers, arithmetical operators, data structures… you name it. With some determination, and a little squinting, we might even see lambda do the impossible: reconcile object-oriented and functional programming. You heard it right: lambda can do it all!

Join me as we explore its astounding computational power, and walk away with a deeper respect and admiration for the almighty little lambda.